Design of general-purpose assistive exoskeleton robot controller for upper limbs

Though research and development on exoskeleton robots have been active recently, the results have limitations in terms of independence from robot platforms and capability for general purposes. This paper presents a novel control scheme named the general-purpose assistive exoskeleton controller (GAEC) for upper limb assistive exoskeleton robots. With only the joint position information used, GAEC is designed to be applicable to any type of upper limb exoskeleton robot platform assisting human worker's common activities. GAEC works in two modes: (1) An external force is neutralized by generation of force with the same magnitude and the opposite direction. (2) The control system complies with the user's own force while maintaining the force that compensates for the external force neutralized in the first mode. In addition to theoretical description of the controller, computer simulation was conducted for validation using a robot model adopted from related studies. Two exemplary working scenarios were considered in the simulation: lifting and moving an object, and tightening a bolt with a wrench.